Recent developments in the design of automobile bumpers or protectors have led manufacturers to construct these parts from thermoplastic or thermosetting materials using designs which enable these devices to undergo elastic deformations in low speed collisions. Upon return to their intial form, the bumpers should not show notable traces of the rigors to which they have been submitted.
Difficulties remain in mounting these parts on the vehicle, since when they are attached by means of metal guard braces, as is frequently the case, these guard braces assume permanent deformations at the moment of impact. As a result, even when the bumper remains apparently intact, its position with respect to the chassis is changed and shows in a permanent way that damage has been suffered.